Feeding device for rock drills



March 20, 1951 w. A. MORRISON FEEDING DEVICE FOR ROCK DRILLS Filed Aug.14, 1948 INVENTOR WILLIAM AMORRISON. BY

a n3 ra in -Eli! I HIS ATTORNEY.

Patented Mar. 20, 1951 FEEDING DEVICE FOR ROCK DRILLS William A.Morrison, Easton, Pa., assignor to Ingersoll-Rand Company, New York, N.Y., a corporation of of New Jersey Application August 14, 1948, SerialNo. 44,249

3 Claims.

This invention relates to rock drills, and more particularly to afeeding device for rock drills of the reciprocatory piston type, thepiston of which is fixedly secured to the working implement which itactuates.

One object of the invention is to control the descending or feedingmovement of the rock drill.

Another object is to enable the resistance to descending movement of therock drill to be conveniently and readily varied in accordance withvariations in the hardness of the material being drilled.

Other objects will be in part obvious and in part pointed outhereinafter.

In the drawings accompanying this specification and in which similarreference numerals refer to similar parts,

Figure 1 is a side elevation, partly broken away, of a rock drillingmechanism equipped with a feeding device constructed in accordance withthe practice of the invention,

Figure 2 is a longitudinal elevation, partly in section, of the motorand transmission elements serving to control feeding movement of therock drill,

Figure 3 is a transverse view taken through Figure 2 on the line 3--3,

Figure 4 is an exploded view showing various parts in perspective, and

Figure 5 is a transverse view taken through Figure 2 on the line 5-5.

Referring more particularly to the drawings, the invention is shownapplied to a drilling mechanism comprising a mounting 20 that supports avertical column 2| to serve as a guide for a rock drill 22. The column2| may, as indicated, be of the type shown in U. S. Patent No. 2,090,479to D. W. Hart, and accordingly comprises a pair of relatively spacedbars 23 of structural shape, the legs 24 of which serve as guides for asaddle 25 carrying the rock drill 22.

The saddle 25 is slidable on the column 2| and carries a lug 23 havingattached thereto the ends of a chain 21 serving as a transmission memberfor a motor 28 to raise and lower the rock drill along the column 2|.The chain 21 is trained over rollers or sprockets 29 at the extremitiesof the column and is looped over a sprocket 30 in a casing 3| on therearward side of the column 2| within convenient reach of an attendantstanding upon the surface supporting the mounting.

The casing 3| may be secured to the column in any well known manner andcontains antifriction bearings 32 for a shaft 33 in the sprocket 2 30.The shaft 33 has keyed thereto a worm wheel 34 between the bearings 32that meshes with a worm 35 constituting an element of a train of gearsserving to transmit motion from the motor 28 to the worm wheel 34. Theintermeshing portions of the worm 35 and the worm wheel 34 have anon-locking pitch so that the pull of the rock drill on the chain duringthe downward movement of the rock drill will cause the worm wheel 34 torotate the worm 35, and on one end of the worm 35 is a gear 36 thatmeshes with a pinion 31 keyed to a shaft 38 which is supported byanti-friction bearings 39 in the easing 3|. The shaft 38 has an end 48in splined engagement with the crank shaft 4| of the motor 28 which isof the reversible, multi-piston type, only one piston 42 of which isshown for reciprocation in a cylinder 43 and having a rod' 44 connectedto the crank shaft 4|.

The distribution of pressure fluid to the pistons 42 is effected by arotary valve 45 which lies coaxial with the shaft 38 and has a stem I9that extends into a recess H3 in a web I! of the crank shaft. The stem|9 may be secured to, or interlocked with, the web I! in any suitablemanner, and in the valve 45 is a passage 46 to register in successiveorder with the inlet passages 41 of the cylinders '43. The valve 45 alsohas a discharge passage 48 to register suc-' cessively with the passages41 and constantly with an atmospheric port 49 in the motor casing forexhausting the fluid from the cylinders 43.

The supply of pressure fluid is conveyed to the motor by a conduit 50,and communication between the conduit 50 and the distributing valve 45is controlled by a throttle valve 5| adjacent the rotary valve 45.,v Thethrottle valve is shown as being of the rotary type having a lever 52,whereby it may be manipulated, and has a central chamber 53 into whichpressure fluid constantly flows from the conduit 50 through an arcuategroove 54 and a port 55, both in the throttle valve 5|.

The arcuate groove is in constant communication with the conduit 50 inthe various controlling positions of the throttle valve 5|, and in theintermediate portion of the throttle valve is a port 56 to register, inone position of the throttle valve, with a passage 51 leading to thedistributing valve 45 for communication with the passage 46 to cause themotor 25 to rotate in one direc tion and, in another position of thethrottle valve 5|, to register with a similar passage 58 through whichpressure fluid is supplied to the passage 46 for operating the motor inthe opposite direction.

In accordance with the practice of the invention, means are provided forcontrolling the descending or feeding movement of the rock drill 22 at arate best suited to maintain the correct operative relationship of therock drill with respect to its working implement 59 which is attached,in a suitable manner, to the reciprocatory element of the rock drill. Tothis end the driving mechanism of the feeding device is provided withbrake means designated, in general, by 60 and comprising a brake shoereciprocable in a cavity 62 in the casing 3| and having a surface 63 tocooperate with a facing of braking material 64 on the end surface of thegear 36. The brake shoe 6| is urged in the direction of the brakingmaterial 64 by springs 65 abutting the brake shoe 6| at one end andseating at their other ends against an adjusting plate 65 which,together with the brake shoe 6|, is held against rotary movement withinthe cavity 52 by a key 61 seated in the casing 3|.

A suitable space exists between the brake shoe 6| and the plate topermit of axial movement of the brake shoe and of adjustment of theplate for varying the force of the springs and, consequently, thepressure of the brake shoe against the braking material 64. Suchadjustment is effected by manually operable means comprising a screw 68having a key portion 69 for interlocking engagement with a slot 10 inthe adjacent side of the plate 66. The screw 68 is threaded into theinner end of a plug 1| rotatable in an end wall l2 of the casing 3|.Both the screen 68 and the plug H are coaxial with the plate 66 and onthe outer end 73 of the plug II is a lever 14 to rotate the plug ll forextending and retracting the screw 68.

The arrangement of the parts within the cavity 62 constituting thebraking device is such that the springs 65 constantly tend to press thebrake shoe against the braking material 64, and means are accordinglyprovided to release the brake, as when lifting the rock drill along thecolumn 2| for removing the working implement 55 from the drill hole orto move the rock drill away from the working implement for the additionof an extension to the working implement in the event that a sectionalworking implement is being used. To this end a plunger 75 is arrangedslidably within the worm 35 to engage, at one end, the brake shoe 6|.

On the other end of the plunger is a head 76 that lies within a cavityT7 in the casing 3| and engages a diaphragm 18 that is clamped at itsmarginal portion between the casing 3| and a cover 19 that cooperateswith the diaphragm T8 to define a chamber 85 for pressure fluid servingto actuate the plunger 15. Such pressure fluid is conveyed to thechamber 30 by a flexible conduit 8| having an end attached to the cover19 and having the other end attached to the portion of the motor casinghousing the valves 45 and 5| to communicate with a passage 82 in themotor casing controlled by the throttle valve 5|.

The valve 5| is accordingly provided with a pair of ports 83 and as thatcommunicate with the chamber 53 and are arranged in such wise that oneof them will be placed in communication with the passage 82 forsupplying pressure fluid to the chamber 80 in either of the positionswhich the throttle valve 5! occupies for valving pressure fluid to thepassages 51 and 58. In the outer surface of the throttle valve, betweenthe ports 83 and 84, is a groove to afford communication between thepassage 82 and the atmosphere fo exhausting the fluid from the chamber80.

In practice, and with the rock drill 22 in operation, the throttle valve5| occupies a neutral position wherein the passages 5'|58 and the ports83-84 are blanked off. In this position of the throttle valve the groove85 registers with the passage 82 so that the chamber 80 will be open tothe atmosphere and the rod 15 will release the brake shoe 6|, which willthen be free to move into engagement with the braking material 64 tocontrol the descending movement of the rock drill 22 at the desiredrate. Whenever it is desired to move the rock drill upwardly along thecolumn 2| the throttle valve 5| is rotated to bring the required portsand passages of the throttle valve and the motor casing intocommunication with each other for rotation of the motor 28 in therequired direction, as for example, by placing the port 58 in registrywith the passage 51.

In this position of the throttle valve the port 83 registers with thepassage 82 and pressure fluid will enter the chamber 86 simultaneouslywith the admission of pressure fluid to the motor. The pressure fluid inthe chamber 80 will shift the plunge [5 and thereby move the brake shoe5| out of engagement with the braking material 54 to release the trainof gearing for free operation.

After the rock drill has been retracted to the desired-position thethrottle valve 5| is returned to its neutral position to cut-off thesupply of pressure fluid to the motor and to exhaust the fluid from thechamber 86 to the atmosphere, thereby, permitting the springs 65 toagain return the brake shoe to its braking position. In the event that,as adjusted, the springs 65 exert an insufficient pressure to hold therock drill stationary, their force may be conveniently increased bymerely rotating the lever '14 to actuate the plate 66 and furthercompress the springs.

Whenever it is intended to lower the rock drill by operation of themotor, the throttle valve 5| is rotated to bring the port 58 intocommunication with the passage 58 thereby supplying pressure fluid tothe valve 45 for distribution to the motor 28. In this position of thethrottle valve the port 84 will communicate with the passage 82 andpressure fluid will flow into the chamber 88 for releasing the brakesimultaneously with the admission of pressure fluid to the motor.

As will be readily apparent from the foregoing description, theapplication and release of the brake to and from the gear train areeffected entirely by the throttle valve serving to control the feedingmotor, and in such wise as to obviate the need of shifting the throttlevalve to positions other than those required for operating the motor.The braking effect of the brake 6|] may, moreover, be conveniently andexpeditiously varied to assure a feeding speed for the rock drillsuitable for the material being drilled by merely manipulating the lever74 to vary the pressure of the springs 65.

I claim:

1. In a rock drill feeding device, the combination of a guide member anda rock drill slidable thereon, a flexible member on the guide memberconnected to the rock drill, a motor for driving the flexible member tolift the rock drill along the guide member for retracting the rock drillfrom a drill hole, a gear train for transmitting motion from the motorto the flexible member, a brake for the gear train frictionally engagingone of the gears of said train to control-'1 the descendingmovementjofthe rock drill along the guide member, fluid actuated meansfor actuating the brake, and a valve for controlling the supply ofpressure fluid to the motor and to the fluid actuated means.

2. In a rock drill feeding device, the combination of a guide member anda rock drill slidable thereon, a flexible member on thgiuide memberconnected to the rock drill, a motor for driving the flexible member tolift the geek drill along the guide'member for retracting" the rockdrill from a drill hole, a gear train for? transmitting motion from themotor to the flexible member, a spring-pressed brake constantly tendingto apply braking force to the gear train, manually operable adjustingmeans for selectively varying the braking force of the brake, a fluidactuated piston for moving the brake out of braking position, and y avalve for controlling the supply of pressure fluid to the motor and tothe piston.

3. In a rock drill feeding device, the combination of a guide member anda rock drill slidable thereon, a flexible member on the guide memberconnected to the rock drill, a motor for driving the flexible member tolift the rock drill along the guide member for retracting the rock drillfrom a drill hole, a gear train for transmitting motion from the motorto the flexible member, a. brake for engagement with one of th gears ofthe train, springs constantly tending to press the brake into brakingengagement withsaid one gear, means comprising a rotary plug and a screwin threaded engagement therewith for'selectively varying the pressure ofthe springs against the brake, a lever on the plug for rotating saidplug to advance and retract the screw, a fluid actuated piston, a rodextending slidably through the geartrain for transmitting movement fromthe piston to the brake for moving the brake out of braking position,and a valve for controlling the supply of pressure fluid to themotor'and to the piston.

WILLIAM A. MORRISON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PA'I'ENTS

